


thirst trap

by redeyedwrath



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Modern Setting, Alternate Universe - Vampire, Biting, Fluff and Smut, Friends to Lovers, Light Angst, Light discrimination (against vampires), M/M, and they were roommates!, mild homophobia, youtuber sylvain
Language: English
Status: Completed
Published: 2020-12-19
Updated: 2020-12-19
Packaged: 2021-03-11 02:08:01
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,002
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28177395
Author URL: https://archiveofourown.org/users/redeyedwrath/pseuds/redeyedwrath
Summary: Felix squints at him. “Are you thirsty?”There’s a beat where Sylvain freezes, but then he settles back into the chair. Hehasto know Felix isn’t offering.“For you? Always,” Sylvain says, and winks. Sometimes, Felix really hates him.“I’m not talking about me. You know I didn’t sign up for the donor program.”-In which, Sylvain is a vampire and also a YouTuber, and he and Felix are roommates
Relationships: Felix Hugo Fraldarius/Sylvain Jose Gautier
Comments: 1
Kudos: 127
Collections: Sylvix Gift Exchange 2020





	thirst trap

**Author's Note:**

  * For [kuropit](https://archiveofourown.org/users/kuropit/gifts).



> ALRIGHTY HELLO! So this was written for Robin for the Sylvix Gift Exchange, I hope you like it!!! The prompt this was written for the prompt "Modern Setting Vampire AU" and I made Sylvain a YouTuber because that's just what I'm like now, apparently. 
> 
> Also thank you to [Allie](https://twitter.com/astronomicallie) for beta'ing this for me and coming up with this absolute BANGER of a title!!! Also also thank you Sylvix server mods for hosting the gift exchange, I had fun <3
> 
>  **Trigger warning:** There's a scene where someone makes a fuss about Sylvain being a vampire, and then jokes in a way that's meant to be insulting that he and Felix, two men, are together

**Thirst Trap (noun)** \- A sexy photograph or flirty message posted on social media for the intent of causing others to publicly profess their attraction. This is done not to actually respond or satisfy any of this attraction, but to feed the posters ego or need for attention, at the expense of the time, reputation and sexual frustration of those who view the image or reply.

* * *

The carollers on the street are the last straw. Felix has been having an awful fucking day so far, and he’s tired, and now people are _singing Christmas carols_ right outside his apartment. They croon loudly about world peace and all Felix can think about is how much he wants them to drop dead. 

He rushes into his apartment building, up the stairs — too impatient to wait for the elevator — and slams the door behind him when he enters. He thunks his head against the wood and just breathes for a second. 

“Hey!” Sylvain says. “What’d that door ever do to you?!”

Sylvain is sitting in the living room, sprawled out in one of the chairs, laptop balanced on his thighs. He’s just barely able to see the entrance from there, and his hair flops to the side when he tilts his head. 

Felix rolls his eyes and walks over to him, then sits down heavily on the couch. “Shut up.”

Sylvain, of course, does not shut up. Instead, he starts in about his day and some of the weird DMs he received. He spent most of the day editing, apparently, which Felix could’ve guessed; he’s still wearing his glasses. 

Unfortunately, Felix has a bad headache right now, so he’s really not in the mood. He presses the heels of his palms into his eyes, and groans. “If you don’t stop talking I’ll un-invite you from this house and you’ll have nowhere to go.”

Sylvain snorts. “Yeah, that only works if I don’t live here.” He brings one of his legs up to kick the outside of Felix’s thigh, sock catching against the denim of his jeans. “Besides, don’t pretend you wouldn’t miss me.”

Felix bats his foot away, and makes a disgusted face at him. “Like you’re staying here for any other reason than that your subscribers like me.” 

“Well, you are pretty easy to look at,” Sylvain says, like it’s nothing. Felix stops. His eyes are still their usual yellow, and his pupils are small, but why else — why else would he —

Felix squints at him. “Are you thirsty?”

There’s a beat where Sylvain freezes, but then he settles back into the chair. He _has_ to know Felix isn’t offering. 

“For you? Always,” Sylvain says, and winks. Sometimes, Felix really hates him. 

“I’m not talking about me. You know I didn’t sign up for the donor program.”

There’s a reason they have donated blood in the fridge that didn’t come from Felix, and that’s the fact that he doesn’t trust himself. He faithfully wears the white _only-in-case-of-emergency_ bracelet, and never once has that case of emergency arrived. 

Felix isn’t about to let a vampire bite him, no matter how much he might trust that vampire. And Sylvain definitely knows that. 

Sylvain sighs, leaning back in the chair. “Just… Never mind.” 

“Whatever. I’ll go warm some bags up for you if you promise to shut up for the rest of the evening.”

Felix knows the way to prepare them by heart at this point. In a pan, with hot water, just like how you’d prepare milk for babies. They even have those non-microplastic bags that contaminate the blood with particles, because Sylvain refuses to drink out of those and he makes frankly ridiculous amounts of money by posting videos of himself on the internet. 

Plus, when they first started living together Felix had warmed up a bag in the microwave, and Sylvain had been sick for days. So yeah, he knows how to prepare them. He could probably do it in his sleep. 

With a headache though… Felix pinches between his eyes and groans. 

“Hey,” Sylvain says, soft, his foot nudging Felix’s ankle. “You okay?” 

“I’m fine. It’s just a headache.” 

Sylvain nudges him again, and Felix opens his eyes — _fuck_ , has the living room lamp always been so bright? — to tell him off, but Sylvain looks. Worried. Eyes big and eyebrows raised, face open.

Sylvain grimaces. “Yeah, I really don’t miss those. Maybe you should have a tylenol.”

“No, it’s fine. I just don’t know why I thought it was a good idea to work in customer service.”

“Honestly? Me neither.” Sylvain grins brightly when Felix glares at him. _Ugh_. “You know, if it keeps hurting, I could also just bite you. My saliva contains —”

What is _with_ Sylvain today? Felix forces himself to keep looking Sylvain in the eyes, despite the throbbing pain behind his eyes, and he can feel his cheeks heating up. 

“Organic painkillers, yes, I know, please stop talking. I’m going now.”

Felix stands up so quickly that Sylvain’s laptop almost falls off his legs. Sylvain scrambles to grab it — unfortunately for him, quick reflexes don’t mean _graceful_ reflexes — and Felix takes advantage of Sylvain’s distraction by making a run for it

Sylvain pouts. “Aw, don’t be like that!”

“Good _night_ ,” Felix says, slamming the door to his bedroom close behind him, because if Sylvain actually touches him Felix knows he’ll never leave. Maybe Sylvain won’t hear how hard his heart is pounding through the wall. 

He sighs. Who is he kidding? 

* * *

Here’s the thing: before Sylvain was a social media personality, and before he was a _vampire_ , he was Felix’s childhood best friend. 

He doesn’t even remember who or what introduced them, exactly, only that something must have. But his early memories are filled with bright red hair, a toothy smile, and brown eyes that glint yellow now. 

Back then, when they were playing, he’d told Sylvain that he wanted to be the father, and Sylvain could play the mother, Sylvain just shrugged and said “okay,” even though he was two years older and therefore obviously way cooler. 

Sylvain knows Felix on a level that not many people do. He knows what Felix was like before, and he knows what Felix is like now, and he doesn’t mind any of it. In return, Felix doesn’t mind the fact that Sylvain needs to drink blood to survive, and that his eyes glow in the dark or that his hearing is really good.

Which is why it sucks that Felix is in love with him. 

* * *

One day, Sylvain stops him when he’s about to flee back into his bedroom. It’s his day off, so he’s still in his pajamas, and he only came out of his blanket cave to smear peanut butter on some toast; he’d hoped to avoid Sylvain, but, well…

“Heeeeey Felix,” Sylvain says, leaning against the doorpost. His arms are bare, and covered in freckles. There’s a small layer of stubble growing on his jawline, shadowing his cheekbones. 

Instead of replying, Felix just raises his eyebrows. 

“Uh, so you may have appeared in the background of one of my most recent vlogs,” Sylvain says. Then he adds, “Accidentally.”

“Accidentally,” Felix repeats, deadpan. 

“Yes?”

Felix violently tears off a bite of toast, and takes pleasure in the way Sylvain pales. “I really hate you sometimes, you know.”

“Lie,” is Sylvain’s only response. Felix takes another bite and pretends it’s Sylvain’s head. Neck. Ears. Anything to get him to stop listening to Felix’s heart. 

“Don’t use your vampire hearing to get out of this.”

Sylvain slumps, running a hand through his hair. The bottom of his t-shirt rides up, and Felix can’t help himself; his eyes slip downward, just for a second, just long enough to see the red fuzzy trail of hair that leads down and...

“Alright, fine, I’m sorry,” Sylvain says, yellow-brown eyes big. Felix already knows he’s going to forgive him. “Let me make it up to you.”

* * *

Making it up to him means taking him out for a couple of drinks, in true Sylvain fashion. 

It’s probably a good thing, because Felix knows that without Sylvain there to drag him out the door every once in a while, he would probably never see his friends. There’s a reason their group chat is named _taking felix out (to dinner)_ **.**

The bar they go to is vampire-friendly. Of course, this means that Sylvain is recognized instantly. As soon as they walk in the door, he’s accosted by two people asking for selfies. Felix tries not to let his disgust show. 

He scans the people in the bar and is — God help him — grateful to see Dimitri waving at him enthusiastically. The table is already very crowded, so Felix grabs an unoccupied chair for another table so that Sylvain’ll have a place to sit. 

"Ah, Felix!” Dimitri says when Felix comes close enough to be accosted by his… Dimitriness. “I am very glad to see you again."

"What he means," Ingrid says, glaring at him, "is that we never see you anymore."

Felix rolls his eyes, leaning back into the booth. “I’m here now.”

“You sure are.” Sylvain winks at him and sets down two glasses — one blood cocktail, one apple juice. He sits down on the chair next to Felix, lower than the bench, so that whenever he shifts their shoulders brush. Felix pretends not to notice.

Dimitri and Ingrid draw him into a conversation about their jobs again — as long as he doesn’t have to talk about his own, he’s fine with it — and he spends most of the evening talking to them. Sometimes, he thinks they might have a point when they tell him they miss him. 

When Sylvain offers to help Bernadetta promote her book again, and Bernadetta squeaks so loudly that some of the other patrons turn around to look at her.

Felix takes a sip of his juice and allows himself a small smile, just this once. 

* * *

Bernadetta is the first to leave the bar, stammering an excuse about needing sleep which everyone knows she won’t get anyway. Maybe it’s because she puts the idea in his head, but Felix’s eyes start to droop after that, and he does his best not to let any of them know. 

But Sylvain catches his eye, tilting his head toward the entrance, and Felix nods. He still seems to have that weird ability of knowing whenever Felix needs him. They say goodbye to Dimitri and Ingrid, grabbing their coats on the way out. 

Felix tries not to look at how Sylvain's red hair shines softly in the light from the bar windows. 

Every once in a while they bump into each other, Sylvain drunk on blood and Felix drunk on him. Sylvain stumbles over a loose tile and Felix presses against his side to steady him, a hand on his shoulder. The tips of his fingers are almost touching the skin of Sylvain's neck.

Side by side, Sylvain is warm and broad next to him. His cheeks are flushed from the blood cocktails, and when he grins at Felix his fangs glint in the light of the streetlamps.

Felix shivers.

 _Bloodsucker_ , someone whispers, and Sylvain freezes. Felix feels his blood run cold, and he turns around to find the asshole who said it, squinting at them. At the end of an adjoining alley stand three kids, probably only just in college, hands buried in the pockets of their hoodies and clearly looking for trouble. 

Felix squints at them, waiting until his eyes adjust to the darkness, and then he strides over to them. Sylvain is still just standing there. 

“Do you have something to say to my friend?” he asks, walking until their chests are touching. He has to look up to stare the guy in the face, but he doesn’t care. He knows he can take him.

The asshole smiles, corners of his lips pulling up. It pulls at his face in a way that makes him look ugly. “Oh, does he suck dick as well as blood?”

Felix flashes hot. He stands up to his full height, still staring the guy down. He hears Sylvain walk over to him, footsteps echoing in the alley, but he pays it no attention. The guy’s smile shrinks at Sylvain’s approach.

Sylvain pulls on his arm, fingers broad over Felix’s skin. “Come on, Felix, let’s just go.”

He knows Sylvain is right; he knows he should just let it go. He’s been talking to his therapist about his anger management issues. So, Felix closes his eyes and breathes out deeply. He glares at the asshole one last time for good measure, breathes out a sharp, “Fine,” and goes to shoulder past Sylvain. 

“We’re not done here,” the asshole says, voice low. Sylvain hisses, but it’s too late. He tries to backhand Felix, but Felix catches his wrist. He squeezes until the bones squeak beneath his fingers. 

“You really shouldn’t have done that,” Felix says. The asshole blinks once, and Felix snaps the bone with a harsh crack. 

The guy drops to the ground, cradling his wrist and eyes wide. Felix smiles at him, and lets his friends drag him off.

A slow rumble echoes through the alleyway. Felix turns around, startled, to see where it’s coming from. Just behind him, crouched low, Sylvain is snarling, eyes flickering a deep red. He tenses, broad shoulders pushing forward, and Felix catches him with a hand around his middle. 

"Stop, you idiot," Felix hisses. "Don't do something you'll regret later."

" _They touched you_ ," Sylvain _growls_ , voice low and deep. He pushes against Felix arms, nails scratching against Felix’s skin, but Felix holds on. If Sylvain wasn’t in predator mode, Felix would’ve punched him. 

"Oh my —" Felix stops, taking a deep breath to gather himself. "Do I look hurt to you?"

Sylvain leans closer. Just a bit. He sniffs, probably to find blood, but Felix knows he’s fine. His hands clamp Felix’s shoulders. The tip of his finger brushes against Felix’s collarbone, and Felix shivers. 

Sylvain’s eyes stay a glowing red, dropping down to his neck.

 _Fuck_ , Felix thinks, and then slowly, almost too slowly too notice, he tips his head back. He can’t help himself. Sylvain stares, eyes still a dangerous red, and Felix shows him the column of his neck, in what is unmistakably an invitation. 

_What the fuck am I doing?_ he asks himself

Sylvain leans forward, so quickly Felix would’ve jumped if Sylvain wasn’t pressing against him so hard, and opens his mouth, fangs pricking softly against Felix’s skin — not breaking it, but still undeniably _there_. Felix’s cock twitches, and he lets himself go limp. 

The moment Sylvain’s lips close around the skin, Felix fists a hand in his hair, pulling him closer. Sylvain’s teeth scrape over his skin, and heat pools low in his stomach, Sylvain’s tongue trailing a slow path over his adam’s apple to the other side of his neck.

Softly, Sylvain bites — not using his fangs, those stay on the edge of breaking skin, using his regular teeth, worrying at it — and Felix can’t help himself. He tugs at Sylvain’s hair and moans so loud it makes him blush, grinding his cock against Sylvain’s thigh. 

Suddenly, Felix shivers as the cold rushes back in. Sylvain’s eyes are wide, fading back to yellow, and his pupils are big in the moonlight. Felix stares at him, head resting against the brick wall behind him, pretending he’s not looking at Sylvain’s panting mouth, his lips wet. 

"Felix,” Sylvain breathes out, and Felix thinks _yes, yes, it’s me_ , but then Sylvain looks away, and Felix feels his heart drop. “I'm so sorry."

Before Felix can say anything in response, Sylvain is gone. 

* * *

A whole day. Sylvain remains gone for a whole entire day. Felix has texted just about anyone he can think of: Sylvain isn’t at Dorothea’s place, or Claude’s, or Bernadetta’s, or Ingrid’s. He feels like he’s losing his _mind_. 

When Sylvain comes back, Felix is going to kill him. 

It’s only because he’s… distracted, that Felix is still awake at four in the morning. His leg is cold where the blanket’s slipped off it, but he’s too lazy to pull it back up. He’s determinedly not thinking about Sylvain when there’s a stumbling noise coming from the living room. 

If he has to deal with a burglar on his own, Felix is going to kill Sylvain even more. He sighs, rubbing a hand over his face, and grabs the baseball bat he keeps underneath his bed. Slowly, he makes his way over to the living room. He tightens his grip on the baseball bat, heart pounding, and creeps over to the kitchen, where a figure is rummaging around in the…

He lets out a breath, putting away the bat. He’s surprised Sylvain hasn’t heard him yet. But, Sylvain looks pale in the harsh light of the freezer — which is when Felix realizes that the idiot probably hasn’t eaten in a day and a half. 

" _Where have you been_?"

"Felix!" Sylvain jumps, almost hitting his head on the top of the fridge. "I, uh…"

Felix turns on the kitchen light, squinting as his eyes get used to the sudden brightness. There are bags under Sylvain’s eyes, and his skin is sickly pale with a lack of blood. His eyes are almost black with hunger. Felix has never been happier to see him. 

He walks up to Sylvain, angry, not caring that the neighbors are going to be complaining about the noise tomorrow morning. Sylvain takes a deep breath, and holds it, face twisting. And that is _it_. 

Felix punches him in the shoulder. "You _fool_. I was so—"

"Listen, Felix, I— I'm sorry. That I left,” Sylvain gasps a breath, chest held high. “And that I tried to bite you."

"That's not. I… I didn't…" Felix groans, leaning against the wall. "Do I really have to say it?"

"Uh," Sylvain says. "Yeah, because I have no idea what you're talking about."

"I," Felix mumbles. "I really wanted you to."

Silence. 

Sylvain breathes out, like a sigh but larger, somehow. Felix forces himself to look at him. The light catches in the hollows of his cheekbones, making him look stark, desperate. Hungry. Sylvain’s eyes are laser-focused on him, and he watches as they dip from his eyes to his mouth to his neck and back to his eyes again. 

"You wanted me to what, Felix," Sylvain demands — he doesn’t ask; his eyes are red and he’s curled in on himself, clamping at his forearm like he wants to grab Felix. 

Felix’s palms are sweating and his heart is pounding so hard that Sylvain can probably hear nothing else. He puts a hand on the wall to steady himself, breathes once, twice, and then looks Sylvain dead in the eye. 

"Bite me."

“Are you sure?” Sylvain asks, low, and now he’s leaning against the fridge like he’s a magnet, like it’s the only thing tethering him to that side of the room, like otherwise he’s going to come over and rip Felix’s throat out. 

Felix scoffs. “You really think I’m going to be squirmy over some blood?”

“It’s not…” Sylvain’s nostrils flare. “You can’t take this back, you know. I don’t think I could—”

And all Felix can say to that, all he could think to say to that, is “I don’t want you to.”

Slowly, so incredibly, achingly slowly, Sylvain stalks forward. Felix keeps himself pressed against the wall, forces himself to stand still. Felix never feels small, but standing so close like this, chests pressed together, Sylvain firm against him, Sylvain feels _large_. 

Sylvain leans down, puts a hand in his hair and softly pulls his head back, his thumb rubbing soothing circles on Felix’s scalp. The hair at the back of his neck is standing on end, and his heart is pounding with the twin feelings of wrongness and _finally, yes,_ **_yes_**. 

“... Did you just sniff me?”

Sylvain hums, his nose trailing down the tendon in Felix’s neck. Heat pools in Felix’s stomach. “You smell nice.”

Sylvain hovers over his neck, coming to a stop at the junction between his neck and his shoulder. Felix draws in a deep breath, his heart thundering so much that Sylvain can probably see it in his veins. 

Then, Sylvain bites. 

Felix whimpers, involuntary, as two needle-like pinpricks slide into his neck. Instantly, the skin around it freezes, and he clutches at Sylvain’s shoulders, digging his nails into the flesh. Sylvain makes a high, keening noise in the back of his throat, his tongue lapping up the first drop of blood, and then he _sucks_.

It’s not unlike the sensation of getting a hickey; Sylvain’s holding him tight, holding him close, and Felix scrambles to pull him even closer, failing because Sylvain seems locked around him. 

Sylvain breathes out once, onto the wound, hot and heavy with blood, and Felix —

A hot flush radiates out from his shoulder, slowly spreading down his arm until his fingertips are tingling. He throws an arm around Sylvain, trying to get him closer, and then Sylvain bites again. 

He clutches at the back of Sylvain’s neck, twining red strands around his fingers and digging his nails into the skin. 

It’s hot, _so_ hot, and Felix doesn’t know what to do with himself, he just pulls Sylvain closer and closer until there’s no space left between them. Sylvain’s leg slips between his to accommodate the new position. 

His blood is boiling, and heat pools in his stomach as the rest of his body freezes, grinding against Sylvain’s thigh. Sylvain chuckles, breath hot against the pinpricks. Felix shivers. 

“Should’ve known you would be into this.”

“Shut up and bite me again,” Felix growls, and he pulls Sylvain’s head down. 

* * *

The clean-up is… awkward. They go into the bathroom at the same time, Sylvain to wipe the blood off his chin and Felix to change out of his come-soaked boxers. They rub against his skin as he moves.

Ugh. Gross.

When he shucks them off, Sylvain winks at him in the mirror, his eyes back to their usual soft yellow. There’s still a trickle of blood running down the corner of his mouth, and he watches, transfixed, as Sylvain licks it off.

God, if he hadn’t just come he’d be hard again. Judging by the way Sylvain glances down, he knows it too. 

“And you wonder why I never signed up to be a donor,” Felix says, getting into his clean pair of boxers. Sylvain’s eyes darken, and he snarls, the tips of his fangs dipping below his upper lip. Felix raises his eyebrow.

“You’re not feeding another vampire,” Sylvain hisses. The red flickers back in, and his shoulders tense. Felix rolls his eyes and throws his dirty boxers at Sylvain’s face, startling him out of it. 

“As if I would, after that.”

Sylvain follows him into the kitchen. If Felix was more self-conscious, he would be pulling his shirt down over his underwear; with the way Sylvain’s eyes track his ass, he just smiles to himself. 

“Good,” Sylvain says, self-satisfied, and he pulls Felix against his side. His hand is warm on Felix’s back, still flushed with blood and smugness. It takes him longer to make a cup of coffee than normal.

“So,” he says once he’s done, blowing on the mug, “what are you going to tell your subscribers?” 

Sylvain hums, light, but his eyes are dark in a way that makes Felix shiver. “Maybe you can make another ‘accidental’ appearance in one of my vlogs.”

Felix punches him in the shoulder. Asshole.

“Hey!” Sylvain says, mock-offended, rubbing over the spot with his free hand and pouting. “What was that for?!”

“I _knew_ it wasn’t an accident,” Felix says, pointing a finger in Sylvain’s face and glaring at him.

“Oops?” Sylvain says, but he’s smiling. Felix rolls his eyes, and does the only thing he can think of that’ll shut Sylvain up. 

He hooks a hand around Sylvain’s neck, and pulls him down to kiss him. 

**Author's Note:**

> THAT WAS IT haha!!! Hope you enjoyed reading ^^ I couldn't help making it a little bit horny because like... c'mon you can't ask me for a vampire AU and expect me to _not_ write a scene where the vampire bites someone and the other person is really into it sdkf
> 
> [My Twitter](https://twitter.com/reverethedeer)  
> [Fic tweet](https://twitter.com/reverethedeer/status/1340397466873700354?s=20)


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